An automobile is equipped with a system that detects a state destructive to safety by processing information obtained using a variety of sensors such as a camera, a radar and the like, to assist driving and to issue an alert to a driver. For example, a collision avoidance support system configured to detect a possibility of collision, to issue an alert to a driver by a sound and the like and to operate an automatic brake has been known. Also, a variety of safety systems such as a lane deviation detection system configured to support maintenance or change of a traveling lane of an own vehicle, an object detection system configured to detect a person and an obstacle on a road, a drowsiness detection system configured to detect drowsiness or side-glance of a driver and to issue an alert to the driver and the like have been used. In most of the safety systems, the driver's attention is called by an indicator, a sound, an image or the like. Also, a system configured to call driver's attention by vibrating a seat on which the driver is seated has been considered (for example, refer to JP-A-2010-029459). A driver's attention recovering device disclosed in JP-A-2010-029459 is configured to detect a driver's attention-lowered state from traveling information such as a steering angle of a steering wheel, and to slide a seat in a left-right direction of a vehicle or to rotate the same in the left-right direction by using an attention recovering drive unit provided in the seat, thereby recovering the driver's attention.
As described above, when a variety of states destructive to the safety of the vehicle driving are detected, for example, when a possibility of collision or lane deviation occurs to the own vehicle or when the drowsiness or side-glance of the driver is detected, the driver's attention is called depending on contents or degree of importance thereof. In the diverse safety systems equipped at the automobile, a variety of attention calling units such as warning sound, voice, indicator, image and the like are used so as to call driver's attention. When a physical sense is provided for the driver by a unit configured to directly stimulate a driver's body together with or instead of an attention calling unit configured to stimulate the driver's senses of sight and hearing, it is possible to call driver's attention more securely. For example, like the driver's attention recovering device disclosed in JP-A-2010-029459, when the seat is provided with the attention calling drive device and the seat is vibrated upon detection of a predetermined state, for example, it is possible to call driver's attention. However, if the seat is provided with the drive device for generating the vibration or the like, it is not only necessary to secure an installation space for the corresponding component but also the cost increases. Also, it is needed to easily and effectively provide the physical feeing for the passenger in accordance with the diverse states detected by the safety systems.